The introduction of digital and analog video recorders has made time-shifting of video information, such as audio and video information, easy for many home entertainment system users. However, a user watching a program will typically change channels when a program interruption occurs, such as a commercial, to perform what is commonly known as “channel surfing”. The video recorder continues to receive the program information and “records” the program information onto the video recorder. Program information may refer to any information, for example, received during a television broadcast. Program information may also include information received from the Internet or from a local database such as a CD-ROM. The video recorder records not only the program the user may be watching but also all the program interruptions, as well as all the portions of programs received during the channel changes also known as “channel surfing.” As a result, when the user later plays back the recording, the video recorder plays back the program that the user viewed, the program interruptions and all the portions of programs as a result of the channel changes. Viewing the program interruptions and, in particular, the portions of programs viewed while changing channels may be undesirable to the user.
Time-shifting of video information allows a user to manually “pause” the reception of the video information by directing the video information to a video recorder while maintaining an instantaneous image of the video information on a television A/V receiver or other video device. The video recorder continues to receive the video information, and “records” the video content onto the digital video recorder. When the user later resumes viewing, the video recorder continues to receive video information and to record the video information onto the video recorder, but presents the video information from a point at which the user had paused the reception. In other words, the user plays video information that is delayed with respect to the video information being recorded. When the user later plays back the recording, the video recorder plays back the program that the user viewed, the program interruptions and all the portions of programs as a result of the channel changes.
According to one method, a digital video recorder includes two tuners, so that while one program is being recorded, another program may be viewed. However, incorporating two tuners into a digital video recorder increases the cost and complexity of the digital video recorder, and therefore is not as desirable as a digital video recorder having a single tuner.
According to another method, a digital video recorder receives electronic program guide information (EPG) during a television broadcast. The electronic program guide information may include broadcast scheduling information, such as the name or title of a program such as a show, the channel the program is broadcast on, the start time and the stop time. The electronic programming guide information may also include other types of information, such as genre (movies, game shows, educational, etc.), channel (NBC, CNN, MTV, etc.), actors (Al Pacino, Dustin Hoffman, Tom Cruise, etc.), and so on. Further, the electronic program guide information may include a narrative summary, various keywords categorizing the content and other suitable information. According to this method, the video recording device may record broadcast information identified by a particular title of a program, such as “Friends.” However, according to this method, any intermediate channel changes are recorded so that when played back, all the intermediate channel changes are also played back.
According to another method, a video recorder is programmed to record an entire program, including all program interruptions. A review of the entire program is performed and program interruptions are marked, based on an estimate of the start of the program interruption and the anticipated length of the program interruption. Once the recording is marked, during playback, scenes that were previously marked are skipped. For example, a video cassette recorder may attempt to identify the start or end of a commercial by detecting changes in audio level. Typically, such methods incorrectly identify the start of a program, resulting in the failure to record a portion of the desired program. Further, these methods may miss the start of a program interruption, resulting in playing a program interruption and possibly skipping over the desired program. Additionally, the method requires recording of both the desired program and all the program interruptions, as well. Therefore, the storage space is wasted, and sufficient storage space is required in order to store all of the programs.